The simplest way to avoid needing to take a sick day is obvious: Stay healthy. But when the first crisp morning of fall signals the beginning of cold and flu season, staying healthy can become difficult.

The first thing you should know is that the best way to prevent the spread of cold and flu is with frequent and proper hand washing. Be vigilant! Make sure to rub your hands with warm soapy water for at least 20 seconds to help to slough germs off the skin.

In addition to hand washing, you can also get a flu shot to prevent influenza—which is especially important this year with the threat of swine flu. Flu activity in the United States generally peaks between late December and early March, so the CDC recommends getting a flu shot in October or November. Within two weeks of getting a flu shot, antibodies develop in your body and provide protection against flu symptoms.

During the peak of cold and flu season, it can be hard to differentiate between symptoms that necessitate sick days and doctor visits and milder symptoms that aren't contagious.